The present disclosure is related to downhole tools used in the oil and gas industry and, more particularly, to a weight down collet that allows a service tool to set weight down only on a desired indicator coupling within a completion string.
In the oil and gas industry, particulate materials such as sand and other wellbore debris are often produced to the surface during the extraction of hydrocarbons from a well traversing an unconsolidated or loosely consolidated subterranean formation. Producing such particulate matter can cause abrasive wear to components within the well, such as tubing, pumps, and valves, and can sometimes partially or fully clog the well, thereby creating the need for an expensive workover operation. Also, if the particulate matter is produced to the surface, it must be removed from the extracted hydrocarbons by various processing equipment at the surface.
In order to prevent the production of particulate materials to the surface, production intervals in the well are often gravel packed, which helps filter out sand and other particulates from the production fluid entering the wellbore. The gravel pack is formed using a gravel pack completion string that is lowered into the well to a position proximate the desired production interval. A service tool is then positioned within the completion string and a gravel slurry is flowed downhole to the service tool where a carrier fluid is separated from the gravel slurry and gravel is left in the production interval as gravel pack. The carrier fluid then reenters the service tool through one or more sand screens associated with the completion string and is returned upwardly through a washpipe section of the service tool. The return flow is directed upwardly through a central passage of the washpipe and then diverted outwardly to an annular flow path through a crossover port.
In some applications, the service tool is used to treat multiple production intervals in a single trip downhole. To accomplish this, a weight down collet associated with the service tool is required to locate and rest on an indicator coupling provided on the inner wall of the completion string. Upon properly locating the desired indicator coupling, the service tool will be aligned with the desired production interval so that downhole operations can be undertaken. While locating the indicator coupling, however, the weight down collet often enters and passes through one or more a seal bores. The friction generated between the weight down collet and the seal bore can prematurely cycle the weight down collet to a weight down position. In such scenarios, the service tool is supported enough to lock up, but is not fully supported. As a result, the service tool can be damaged or the weight down collet can fail.